horizontal lines 21 videos

Line Segments
Geometry Geometry Building Blocks
How to define and label a line segment.
line endpoint points 
Constructing a Perpendicular at a Point on a Line
Geometry Constructions
How to construct a perpendicular line at a point on a line.
perpendicular point on the line construct 
Parallel and Skew Lines
Geometry Geometry Building Blocks
How to mark parallel lines, how to show lines are parallel, and how to compare skew and parallel lines.
parallel lines skew lines coplanar collinear 
Parallel Planes and Lines
Geometry Geometry Building Blocks
How to identify parallel lines, a line parallel to a plane, and two parallel planes.
parallel lines skew plane 
Converse of Parallel Lines Theorem
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to take the converse of the parallel lines theorem.
parallel lines theorem transversal 
Constructing a Perpendicular to a Line
Geometry Constructions
How to find the shortest distance between a point and a line.
construction midpoint perpendicular equidistant shortest distance to a line 
Proportional Segments Between Parallel Lines
Geometry Similarity
How to prove two triangles are similar using a line parallel to a base.
parallel lines triangles similar triangles proportion 
Three Undefined Terms: Point, Line, and Plane
Geometry Geometry Building Blocks
How to describe and label point, line, and plane. How to define coplanar and collinear.
point line plane coplanar collinear 
Cyclic Quadrilaterals and Parallel Lines in Circles
Geometry Circles
How to prove that opposite angles in a cyclic quadrilateral are congruent; how to prove that parallel lines create congruent arcs in a circle.
inscribed angles cyclic quadrilaterals parallel lines alternate interior angles 
Duplicating a Line Segment
Geometry Constructions
How to duplicate a line segment using a compass and straightedge.
congruent segments construction compass straightedge 
Constructing Parallel Lines
Geometry Constructions
How to construct parallel lines using three different methods.
transversal duplicating angles corresponding alternate interior alternate exterior 
Vertical Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to define and identify vertical angles.
vertex intersecting lines congruent 
Corresponding Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to define corresponding angles and their special properties.
parallel lines angles congruence 
Rays
Geometry Geometry Building Blocks
How to identify, define, and label rays and opposite rays.
ray line endpoint opposite rays 
Alternate Interior Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to define alternate interior angles and their special properties.
parallel lines angles congruence interior transversal 
Alternate Exterior Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to define alternate exterior angles and their special properties.
parallel lines angles congruence exterior transversal 
Same Side Interior and Same Side Exterior Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to describe same side interior and same side exterior angles and their special properties.
parallel lines angles congruence interior exterior transversal 
Constructing an Angle Bisector
Geometry Constructions
How to define and construct an angle bisector.
construction perpendicular equidistant shortest distance to a line bisector 
Radii to Tangents
Geometry Circles
How to define a tangent line; how to determine the angle a radius to a tangent forms.
tangent radius right angle point outside the circle perpendicular 
Glide Reflections
Geometry Transformations
How to describe a glide reflection and identify the information needed to perform a glide reflection.
composition of transformations translation glide reflection parallel lines ordered pair rule